One item i read a little bit ago was that it can interfere with WIF if it is close to your router. So you could try it out and if your 2.4ghz wifi starts to run poorly then look at turning it back down. That same thread called out that 16 is twice as powerful as what the C7 did so you are already getting more power from it.
Honestly I'd keep it at 16. As @mavrrick58 points out the C7 was at 8 so you're already getting double the output, plus the additional benefit of the external antenna. As the power output of the radio increases so does its sensitivity, which makes it theoretically more susceptible to interference.
I ran mine at 16 for a while, then dropped back down to 8, and it's been pretty happy.